Semiconductor wafer fabrication plants typically produce thousands of devices per day and may be configurable to fabricate two, three or more different product groups/types. E.g. commercial 8 inch wafer fabrication plants costs typically US$1.5 billion to build, representing a significant capital investment for even the largest enterprises.
Profitability is of vital importance to the operators and owners of wafer fabrication plants, and such people endeavour to improve profitability without relying only on further capital expense in installed equipment. There thus is a need to optimise the use of existing installed equipment.
As mentioned, wafer fabrication plants will produce more than one semiconductor product. Conventionally, the mix of products being manufactured at any one time is based on a demand plan and a derived corresponding initial capacity plan. Such initial capacity plans are reactive to customer ordering, and associated with a tooling plan. But conventional initial capacity plans are not optimised, and thus there is a need to improve upon them, with the goal of improved profitability or plant output.